Bulletin of the American Physical Society
43rd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 57, Number 5
Monday–Friday, June 4–8, 2012; Orange County, California
Session J5: DAMOP Thesis Prize Session |
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Room: Garden 3 |
Wednesday, June 6, 2012 2:00PM - 2:30PM |
J5.00001: Quantum gas microscopy: an atomic scale probe of strongly-correlated many-body systems Invited Speaker: Waseem Bakr Ultracold atomic systems can be used to simulate a range of phenomena in strongly-correlated materials ranging from high-T$_{c}$ superconductors to quantum magnets. The micron-scale spacing of atoms in these systems provides an opportunity to optically image fluctuations and correlations in strongly correlated systems in a way not possible in condensed matter. In this talk, I will present quantum gas microscopy (QGM), which allowed for the first time, optical imaging and manipulation of strongly-interacting quantum gases containing thousands of atoms at the single atom level. I will describe a range of experiments we realized using this technique, including site-resolved imaging of atom number fluctuations and correlations across the superfluid to Mott insulator transition in an optical lattice, and the first simulation of a lattice spin system, exhibiting a quantum phase transition between antiferromagnetic and paramagnetic phases. QGM also allowed us to observe orbital excitation blockade, which we used for algorithmic cooling of lattice gases. The ideas introduced in QGM are quite general and can be applied to a range of other systems including fermionic and dipolar gases. In addition, it provides a path to quantum computation in a system with a scalable architecture. [Preview Abstract] |
Wednesday, June 6, 2012 2:30PM - 3:00PM |
J5.00002: In situ probing of two-dimensional quantum gases Invited Speaker: Chen-Lung Hung Experiments on ultracold gases offer unique perspectives to unveil many-body phenomena near phase transitions described by paradigmatic condensed matter models. In this talk, I will present new insight from spatially-resolved, in situ images of ultracold atoms confined in a two-dimensional (2D) trap, with a focus on critical regions of continuous phase transitions. In situ imaging of a monolayer of 2D gas reveals precise atomic density distributions, providing advantages in studying equilibrium thermodynamics, transport properties, as well as density fluctuations and spatial correlations away from thermal equilibrium, many of which are difficult to resolve in conventional bulk measurements. Using samples prepared at various temperatures and atomic interaction strengths, we confirm scale invariance and universality of weakly interacting 2D gases near the Berezinskii-Kosterlitz-Thouless transition, and verify the theory describing its critical behavior. Density-density correlations and static structure factors are also extracted, revealing intriguing quantum behavior of underlying many-body phases. By loading a 2D gas into a square lattice potential, we induce the superfluid-Mott insulator quantum phase transition, and observe the emergence of quantum criticality at low temperatures. Our study reveals different time scales for global mass transport and statistical evolution, opening up new prospects to investigate dynamical criticality near quantum phase transitions. [Preview Abstract] |
Wednesday, June 6, 2012 3:00PM - 3:30PM |
J5.00003: Cavity-Enabled Spin Squeezing for a Quantum-Enhanced Atomic Clock Invited Speaker: Monika Schleier-Smith For the past decade, the stability of microwave atomic clocks has stood at the standard quantum limit, set by the projection noise inherent in measurements on ensembles of uncorrelated particles. We have now, in proof of principle, surpassed this limit by operating with atoms in a particular type of entangled state called a ``squeezed spin state.'' The generation of non-classical spin correlations in a dilute cloud of atoms is facilitated by an optical cavity, which allows for strong collective coupling of the atomic ensemble to a single mode of light. Since the light exiting the cavity is entangled with the atoms, an appropriate measurement performed on the light field can project the atomic ensemble into a squeezed spin state. We have demonstrated 3.0(8) dB of spin squeezing by this method of quantum non-demolition measurement. We have further developed a new method, cavity feedback squeezing, which uses the light field circulating in the resonator to mediate an effective interaction among the atoms. The states prepared by cavity feedback are intrinsically squeezed by up to 10(1) dB and detectably squeezed by up to 5.6(6) dB. Applied in an atomic clock, they produce an Allan variance 4.7(5) dB below the standard quantum limit for averaging times of up to 50 s. [Preview Abstract] |
Wednesday, June 6, 2012 3:30PM - 4:00PM |
J5.00004: Molecular interactions in and with fields: thermal collisions, ultracold gases, supersymmetry Invited Speaker: Mikhail Lemeshko The work to be presented in this talk is chiefly concerned with developing new techniques to manipulate molecular states and interactions by means of static and radiative fields. The talk will describe a simple analytic model to rationalize molecular collisions, both field-free and in fields; techniques to fine-tune and probe weakly-bound molecular states and to enhance the photoassociation rate of ultracold atoms with far-off-resonant light; the use of supersymmetric quantum mechanics to find exact solutions to the eigenproblem of molecules subject to a particular combination of fields; new types of intermolecular potentials shaped by far-off-resonant light. Of relevance to ongoing experiments, this work offers insights into few-body AMO physics and may induce the study of many-body effects it anticipates in the collective behavior of ultracold gases. [Preview Abstract] |
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